(1) Field of Invention
Manually manipulatable device for inserting, holding, and removing soft contact lenses.
(2) Description of Prior Art
Suction cup types of devices for insertion, manipulation, and removal of hard contact lenses are known in the art. However, these prior devices are not functional with respect to soft contact lenses. Heretofore the soft lenses have been inserted in the eye by placing a properly prepared and wetted lens on the index finger and using the finger to move the lens into contact with the cornea, whereupon the lens adheres to the eyeball due partly to suction and partly to capillary attraction. Generally, the posterior face of the soft lens has a range of curvature which preferably approximates that of the cornea. The lens is very thin and pliable and, when applied to the cornea, tends to assume a shape in which the curvature of the posterior face is the same as that of the cornea. In doing so, the lens developes sufficient suction or capillary attraction to adhere sufficiently to the cornea so that it cannot be directly pulled off by pulling forces applied in a direction directly away from the eye parallel to the anterior-posterior axis of the lens. Such lenses cannot be removed by the conventional suction cups because the lens itself becomes, in effect, merely an extension or enlargement of the cup.
Presently such a soft contact lens is removed by slipping the lens by the finger in a direction laterally from its normal position on the cornea to an eccentric position, usually inferior-temporal to the cornea. Thereupon, due to the difference in radii of curvature of the posterior face of the lens and the sclera causes the lens to wrinkle or buckle, thereby allowing air to enter the space between the eye and lens. The entrant air breaks the adherence of the lens to the cornea, whereupon the lens can be pinched between the fingers sufficiently to release it entirely. This removal can be initiated only in the eccentric position of the lens, wherein the radii of the cornea and posterior face are different from each other.
Manipulation of the lens in preparation for insertion also is done by the fingers, with occasional inadvertent inversion or turning of the lens inside out. When such inversion occurs, the lens must be reverted before it can be installed, and such must be done very carefully to avoid damage to the lens surfaces and edges. Also, the fingers, especially the nails, may strike and damage the eye during insertion or removal of the lens, and infection from the fingers is an additional danger.